The NIH Look AHEAD Study
A recent update from the NIH Look AHEAD study, a long-term lifestyle intervention trial for obese patients diagnosed with Type 2 diabetes, concluded that the intensive interventions did not impact outcomes for cardiovascular events and deaths. The "surprising result" made headlines in the New York Times and other news organizations.
The official NIH statement described how 11 years of lifestyle intervention resulted in an average 5% weight loss for participants, but no associated decrease in rates of heart disease, stroke, heart attack, and cardiovascular-related deaths.
Results in Context
While results like those from the NIH study may initially seem discouraging proponents of lifestyle change, there are several considerations that put the results into context. First of all, the "meaningful weight loss" achieved by the study was only 5% of initial body weight for the overweight and obese participants. For an overweight individual, clinically defined as having a BMI greater than 25, that may mean dropping from 170 to 161.5 lbs (if you are 5'7"); for an obese individual, whose BMI exceeds 30, that weight loss could be going from 200 to 190 lbs (also based on being 5'7"). These decreases in body weight are laudable, but in neither case constitutes sufficient weight loss to be no longer considered overweight or obese, respectively.
Put this way, the results of the study could be interpreted in two ways: 1) that the lifestyle intervention maintained over the course of the study was not intensive or perhaps efficient enough to produce significant weight loss, which was the factor directly impacting cardiovascular risk; or 2) that intensive weight loss effort is futile to pursue past a certain threshold in patients who have progressed to the full diabetic disease state. Since the NIH protocol defines its interventions by low-fat diet and increased exercise, we wonder whether the nature of prescribed diet (for which the primary option was two meal-replacement shakes and a frozen dinner entree) and types of exercise (175 minutes/week) may have been too narrow a program for "lifestyle intervention." Also, we worry whether characteristics of full-blown diabetes actively undermine the efficacy of certain interventions--a conclusion that would impact the seriousness of the diagnosis, and necessitate intervention prior to diagnosis all the more.
Put this way, the results of the study could be interpreted in two ways: 1) that the lifestyle intervention maintained over the course of the study was not intensive or perhaps efficient enough to produce significant weight loss, which was the factor directly impacting cardiovascular risk; or 2) that intensive weight loss effort is futile to pursue past a certain threshold in patients who have progressed to the full diabetic disease state. Since the NIH protocol defines its interventions by low-fat diet and increased exercise, we wonder whether the nature of prescribed diet (for which the primary option was two meal-replacement shakes and a frozen dinner entree) and types of exercise (175 minutes/week) may have been too narrow a program for "lifestyle intervention." Also, we worry whether characteristics of full-blown diabetes actively undermine the efficacy of certain interventions--a conclusion that would impact the seriousness of the diagnosis, and necessitate intervention prior to diagnosis all the more.
Of course, the cardiovascular outcomes are only one metric for assessing the value of lifestyle intervention. Other dimensions of health, such as mobility, mood, sleep, and overall quality of life may respond in a more encouraging manner to sustained lifestyle change in diabetic individuals.
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